Craftable Characters

How often does TC add in new Craftable characters and how do they choose which characters to make craftable. I feel like with these real crappy pack odds, they should make the characters that come out that weekend craftable for just that weekend. They cost of the craft should go down as you open alot of packs for that playable character(EX: 1 Armored Kantus Pack opened, would result in 2400 scrap, but 5 Armored Kantus packs opened would result in 1800 Scrap) They should have a poll where the community votes which they want to be released each and every weekend. At the end of the month we get to vote on which characters we want to be permanently craftable. With a community as tiny as it already is we should atleast have the say in which players we want to play as.